Spark arrester



R. B. BOURNE SPARK ARRESTER Aug. 22, 1939.

Filed Aug. 5, 1937 2 Sheets-Sheet 1 M Z 025 R f Ofi W mm m WA T m Aug. 22, 1939. R. B. BOURNE 2,170,704

SPARK ARRESTER Filed Aug. 3, 1937 2 Sheets-Sheet 2 INVENTOR Roz/M0 B, Bow/v: BY

TORNEYS Patented Aug. 22, 1939 UNITED STATES PATENT OFFICE SPARK ARRESTER Application August 3, 1937, Serial No. 157,171

3 Claims.

The present invention relates to devices having as their primary function the trapping of sparks and particles of carbon which ordinarily accompany the exhaust of internal combustion engines. The spark arresters described in the present application are especially adapted for use on Diesel driven tractors where low cost. light weight, small size, eflicient spark arresting and moderate mufiling of the noise are the prime requirements.

In all the embodiments shown, the exhaust gases are caused to whirl about an horizontal axis instead of about a vertical axis, as is usually the practice. The dirt separating means is placed so that the direction of the sparks and particles is downward thereinto without any substantial change in direction. This results in a very high efiiciency for the device as a spark arrester, and permits the use of smaller separating chambers than have heretofore been found practical.

Referring to the drawings:-

Fig. 1 is a section on line ll of Fig. 2, of one embodiment of the invention;

Fig. 2 is a section on line 22 of Fig. 1;

Fig. 3 is a transverse section on line 33 of Fig. 4, of another embodiment of the invention;

Fig. 4 is a section on line 4-4 of Fig. 3;

Fig. 5 is a side elevation of the embodiment shown in Fig. 3;

Fig. 6 is a detail of the embodiment shown in Fig. 3;

Fig. 7 is a section on line 1-1 of Fig. 8, showing a preferred embodiment of the invention; and

Fig. 8 is section on line 88 of Fig. 7.

Referring to Figs. 1 and 2, the device comprises an elongated flat casing I formed by fiat side members 2, 3 and a peripheral member 4 which is divided into an upper semi-circular portion, a central straight portion and a lower semi-circular portion as shown in Fig. 1. A centrally disposed bottom inlet connection 5 permits the exhaust gases to enter the whirl chamber 6 through a slot-like passage 1 formed between the member 4 and a curved vane 8 which extends transversely from the flat side 2 to the opposite side 3. This member 8 is so shaped that the exhaust gases are led into a peripheral motion without undue back pressure and the upwardly concave portion thereof is extended as shown, on a radius equal to that of the upper portion of the casing, soas to coact with the latter to form a cylindrical whirl chamber having a peripheral, slot-like inlet opening 9 and a peripheral, slot-like opening In which forms the entrance to a dirt box II. A removable plate I2 is provided for emptying the accumulated dirt. An outlet connection l3 extends downwardly through the member 4 into the interior of the device to a point, substantially in the center of the cylindrical whirl chamber, where the whirling exhaust gas is free of entrained dirt. A radially curved vane 14 extending between the sides 2 and 3 is provided for the purpose of ensuring that the peripherally moving sparks will continue along the upper inner surface of the easing and thus be trapped in the compartment Ii; otherwise a few particles will strike the side of the conduit 13 and be deflected down toward the inner open end I5 thereof whence they may be carried out. A cover plate 16 on one side of the casing I permits access through the opening I! to the interior of'the device. The peripheral opening I0 is made rather narrow to prevent turbulence in both the whirl chamber 6 and in the dirt compartment II. The leading edge N3 of the member 8 is preferably ground sharp in order to minimize bouncing of particles therefrom. This feature is especially important in the case of live sparks which behave as though they were highly elastic bodies.

The embodiment shown in Figs. 3, 4, 5 and 6 comprises the cylindrical casing I9 having a fixed flat side 20 and a removable flat side 2| whereby the entire interior is accessible for cleaning. A tangential bottom inlet conduit 22 opens into the interior of the casing [9 through the opening 23 whereby the entering exhaust bases and entraineddirt are given a whirling motion around the inside periphery of the casing 19. The sparks and dirt fall into the dirt box 24 through the peripheral slot-like opening 25 without any change in direction. This accumulation may be removed taking off the screw cap 26. A curved vane 21 disposed substantially as shown, extends from the side 29 to the side 2| and is provided for the purpose of smoothing out the gas flow across the opening 25 and for spreading out the incoming gas as it enters through the inlet opening 23. The exhaust gases leave the whirl chamber through the outlet conduit 28, disposed coaxially with the cylindrical casing l9. This con duit 28 is provided with a slot-like opening 29 which extends longitudinally along the conduit 28 from points appreciably removed from the flat sides 28, 2| so that fine particles which have been slowed down in their whirling motion by friction along the flat sides of the casing will not be swept into the outlet opening 29. This is an important feature of the invention. This slot-like opening 29 extends about half way around the conduit 28 and its center is directed approximately at the opening 25. In constructions where no removable side plate 2! is used, the conduit is extended so as to be afiixed to both flat sides thus giving additional strength to the structure as in Fig. 8. Otherwise, the interior end of the conduit 28 is closed by the circular disc 3|. The end of vane 21 adjacent the opening 25 is preferably sharpened similarly to member 8.

Figs. '7 and 8 show a preferred embodiment of the invention comprising a U-shaped casing 332 closed at its bottom end by the plate 33 and on its sides by the fiat plates 34, 35 respectively. An interior vane 36, extends from the header 34 to the header 35 and is curvedto the same radius R and on the same center as the upper portion of V the casing 32. This vane, together with the casing 32 and sides 34, 35, forms an annular whirl chamber 31. The vane 36 is so proportioned and disposed that there is formed a slot-like peripheral opening 38 serving as an inlet for the exhaust gases, and a peripheral slot-like opening 39 through which the entrained sparks and dirt are removed from the gas stream. The area of the opening 38 is made to conform with a proper velocity of exhaust gas whereby a vigorous whirl is obtained without undue back-pressure. The slot 33 extends from the header 34 to the header 35 and is made relatively narrow so that its presence will not create turbulence in the whirling gas stream nor in the dirt compartment 40 into which it leads. This compartment 46 is separated from an inlet compartment 4| by the transverse partition d2 extending from the bottom of the vane 36 to the bottom plate 33. Accumulated dirt is removed from the space 40 through an opening 43 in the plate 33. This is normally closed by a plug M. Exhaust gases enter the chamber 4| through the bottom inlet connection 45, pass upwardly through the opening 38 and whirl about the horizontal axis of the chamber 31, the dirt being separated out through the opening 39. The edge 5! of the vane 36 is ground sharp. The exhaust gases leave the chamber 31 through the slot 45 in the coaxially disposed outlet conduit l which extends from the plate 34 to the plate 35, passing through an opening 48 therein and thence to atmosphere. A tail pipe may be fitted by means of the connection 49. The slot 45 extends longitudinally along the conduit 41 between points removed appreciably from the side walls of the casing, for reasons stated in connection with the embodiment of Fig. 3. Peripherally, the slot embraces about 120 degrees. as shown by the. angle d, Fig. '7, and is pointed downward. The embodiment of Figs. 7 and 8 is highly effective as a dirt separator and may be made to sell at a low price. By having an eccentric bottom inlet and a side outlet, the exhaust gases may be pointed in any desired direction. Should it be desired to have the exhaust take place vertically, this is readily accomplished by means of a degree L and short tail pipe.

In operation, the dirt and sparks may make several convolutions before being finally trapped in the dirt box. All the dirt entering the whirl chambers of any of the embodiments shown herein eventually is deposited in the dirt box. Even large quantities, far in excess of that ever to be expected in service, are eifectively separated out. Should the slot-like opening leading into the dirt box ever become clogged, it may be readily cleaned with a suitable tool inserted through the hole in the bottom of the dirt box.

The high efliciency of the spark arresters shown herein is largely due to the unique and novel methods used. Live sparks fall naturally into the dirt box. There is no tendency to disturb the separating action even under extreme conditions of overload. The dirt collecting chambers are made large compared to the width 7 of openings thereinto, to minimize turbulence. The collected dirt, once in the dirt box cannot be re-circulated in the whirl chamber. Live sparks are extinguished quickly.

removing collected dirt therefrom and a coaxially disposed outlet conduit extending from an opening in one of said end closures to the other, said conduit having a rectangular opening in one side thereof and extending along the length of said conduit between points appreciably removed from said end closures.

2. A dirt separator in accordance with claim 1, wherein is included a radially curved vane extending in a longitudinal direction the full length of said cylindrical whirl chamber and in a peripheral direction between points substantially removed from the exterior of said outlet conduit, the radial distance between the vane and the outer surface oi said whirl chamber being sufiicient to permit entrained dirt to pass therebetween.

3. A dirt separator comprising inner and outer wall members and end walls defining between them an annular whirl chamber, the outer wall member being formed toprovide spaced circumferential gaps and tangential walls of opposite incidence located on remote sides of the spaced gaps, an inlet duct coupled to the casing to connect with one of the gaps and bounded in part by one of said tangential walls, a. dirt receptacle coupled to the casing to connect with the other of said gaps and bounded in part by the other of said tangential walls, the inner wall member having an opening therein to provide a gas outlet.

ROLAND B. BOURNE. 

